Post navigation

Testimony of Dr. Jennifer Yttri on pedicle screw spinal systems

May 22, 2013

I am Dr. Jennifer Yttri and I am speaking today on behalf of the National Research Center for Women & Families. Our organization does not accept funding from device manufacturers and therefore I have no conflict of interest.

Our nonprofit research center includes scientists and medical and public health experts who analyze and review research on a range of health issues. We respect the work of the FDA and our president, Dr. Diana Zuckerman, serves on the boards of two non-profit organizations dedicated to providing FDA with the resources needed to do their job.

Over the past dozen years, we have provided comments to the FDA regarding classification of medical devices. We have extensive knowledge of the processes involved in reviewing new medical devices. But our primary concern is public health, and making sure that patients and their physicians have accurate, objective, and understandable information about medical products on the market.

The patients being discussed today have low-grade spondylolisthesis or degenerative disc disorder. Their reduced clinical severity means their benefit to risk ratio is very different from patients with more severe disease, that this committee has previously considered.

The risks of using traditional, rigid, pedicle screw spinal systems are similar regardless of the severity of the condition. Although the risks seem to be quite low, they can be serious: device failure requiring surgery, vascular injury, and pseudoarthrosis. These risks must be compared to the proven benefits. Is the outcome of surgery better or worse without these pedicle screws? I’m not talking about comparative effectiveness to other devices, but it is essential to prove that this device used in surgery is better than surgery without this device. Spinal fusion rate might be better, but there is no clear benefit on factors important to patients, such as improved function and reduced pain. In the absence of clear evidence that the pedicle screws benefit patients, why subject a patient to any increased risk for questionable benefit? They are certainly worse than nothing in terms of safety.

Currently, there are pedicle screw systems on the market that have been used for years and don’t seem to do much harm, whether or not they do much good. However, your advice today will influence FDA’s decision applying to all manufacturers making any of these screws in the future.

By definition, pedicle screws used for spinal surgery are high risk devices because they can sustain life or make life miserable. The law therefore states these are Class III devices and should be subject to testing in clinical trials. While pedicle screw systems currently on the market may be safe and effective, the classification of these devices will affect NEW products, and without clinical trials we don’t know if those are safe OR effective.

If the FDA down-classifies these systems as proposed, new pedicle screw systems made in the future will not be required to be tested in clinical trials to make sure they are safe and effective. The only testing required would be biocompatibility, sterility, and mechanical testing controls for a Class II device. Mechanical testing and labeling controls are insufficient substitutes for measuring what happens inside a patient.

We frequently make presentations to medical audiences and public health experts. They have been shocked to learn that implanted devices often are not required to be tested in clinical trials. The lack of clinical testing has undermined their confidence in these implants.

All of us want patients to have access to medical devices and procedures that are safe and effective. You may be confident that the pedicle screws currently available to these patients are safe and effective. BUT none of us can know whether new devices made in the future, by other companies or using new designs, will also be safe and effective.

Please protect patients and their physicians by urging the FDA to require clinical trials for these pedicle screws. This should be done by PMA for a Class III device, but if you prefer to compromise, you could recommend that clinical trials be required as a special control for a Class II device.

The bottom line: clinical trials are needed to ensure these screws are reasonably safe and reasonably effective.